OFFSET
1,1
COMMENTS
Column 2 of A219373.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/13440)*n^8 + (1/3360)*n^7 + (1/576)*n^6 + (41/240)*n^5 - (9419/5760)*n^4 + (2009/160)*n^3 - (70291/2016)*n^2 + (42649/840)*n - 29 for n>1.
Conjectures from Colin Barker, Mar 11 2018: (Start)
G.f.: x*(4 - 23*x + 87*x^2 - 215*x^3 + 349*x^4 - 353*x^5 + 219*x^6 - 84*x^7 + 25*x^8 - 6*x^9) / (1 - x)^9.
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.
(End)
EXAMPLE
Some solutions for n=3:
..0..0....0..0....1..1....2..2....0..0....0..0....2..1....1..0....2..0....2..0
..0..1....0..1....1..1....2..2....0..0....0..2....1..1....0..0....0..0....0..0
..2..3....3..1....2..3....2..3....0..1....2..2....1..1....2..0....2..0....3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2012
STATUS
approved